At what bilirubin level should I consider phototherapy for a newborn with jaundice?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 17 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Phototherapy should be considered in babies with a serum bilirubin level that exceeds the treatment threshold for their age, as indicated in the threshold table and treatment threshold graphs .

Specifically, in babies who are more than 24 hours old and have a gestational age of 38 weeks or more, phototherapy is started when bilirubin levels are above the thresholds specified for their age in hours (e.g., >200 micromol/litre at 24 hours, >250 micromol/litre at 48 hours, etc.) .

In babies with a bilirubin level within 50 micromol/litre of the threshold, repeat measurements are recommended to determine if phototherapy is needed .

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